Dynaudio Special Twenty-Five loudspeaker

Not every interesting audio component gets a full review in Stereophile. Many more products are covered in Sam Tellig's, Art Dudley's, Michael Fremer's, Kal Rubinson's, and John Marks' regular columns than I have the space to publish measurements for. However, I do ask for samples of products that I feel deserve to be measured, particularly when our original coverage raised more questions than it answered.

Such was the case with Dynaudio's Special Twenty-Five loudspeaker, released in 2002 to celebrate the Danish manufacturer's 25th anniversary. A fairly large, stand-mounted, two-way design, the Twenty-Five costs $5200/pair. The speaker's tweeter is Dynaudio's superb Esotar 2 1.1" soft-dome unit, also used in Dynaudio's Confidence C4 speaker, which I enthusiastically reviewed in March 2003. The crossover is said to be first-order in nature, and the 8" plastic-cone woofer is reflex-loaded with a large flared port on the Twenty-Five's rear panel to give a claimed bass extension of –3dB at 35Hz.

The Twenty-Five was covered (briefly) by John Marks in his January 2003 "The Fifth Element" column. "How do they sound?" asked JM. "Fabulous," JM answered. "No excuses needed on organ music, or on Brahms' Ein deutsches Requiem. Female vocals are just beguiling, string quartets riveting."

That's pretty much all he wrote. The controversy arose when it came time to compile the magazine's "Recommended Components." In what class should the Special Twenty-Five be rated? The fact that the speaker's low frequencies don't extend down to 20Hz rule out a full-range recommendation, but should it go in Class A (Restricted Extreme LF), which is what JM's enthusiastic encomium suggested, or in Class B (Restricted LF), which is what common sense and my own auditioning at that time suggested?

Class B is what I decided on, which is where the speaker has resided since the April 2003 listing—but not without complaints from readers, who felt it was better than some speakers that we rated Class A, or that it had more bass extension than its specification suggested. John Marks went online to discuss the matter, writing in November 2003 on the Audio Asylum that he did "have twinges when I have to give a great product like the Dynaudio 25th Anniversary speaker a Class B rating, because it in fact is not the best in its class that can be achieved regardless of cost." He concluded that his admiration for the Dynaudio Twenty-Five "remains intense. Audition it if you can. It is a wonderful speaker and I can easily envision it being the 'final speaker' for many people."

I promised that I would resolve these issues by auditioning the speaker in my own listening room and producing a full set of measurements. Accordingly, JM sent me the pair of Special Twenty-Fives he had written about, serial numbers 095 and 096, which are finished in a beautiful-looking blonde birch veneer. I've used the speakers at infrequent intervals since January 2004; here, finally, are my own feelings.

Sound
The Special Twenty-Fives were used on 24" Celestion stands, the central pillars of which were filled with a mix of lead shot and dry sand. The stands put the tweeters at my ear level.

I used the speakers with their ports open, the balance sounding too lean in my room with the ports blocked. I tried very hard to get a reasonable bass balance with the speakers well away from room boundaries, in the positions where the MartinLogan Montages had worked best, but even though the low bass was extended (see fig.7 in the measurements section), it was hard to get sufficient midbass weight without some boundary reinforcement. I therefore moved the speakers back a little and closer to the sidewalls, which gave the optimal integration through the bass without smearing the Dynaudio's low-frequency definition, which was excellent for a reflex design.

The Twenty-Five's bass was full and well-extended, even the 25Hz warble tone on Editor's Choice (CD, Stereophile STPH016-2) being clearly audible. The 20Hz tone was missing in action; even so, I never felt music to be deficient in low frequencies. The Fender bass on Editor's Choice had terrific weight, considering the speaker's relatively small size. Likewise, orchestral double bass sounded rich and full.

"Smooth, smooth, smooth," say my listening notes, and from the first note of the first recording I played on the Special Twenty-Fives to the last note of the final CD, the impression persisted of a grain-free ease to the speaker's midrange and highs. Female vocals were indeed "beguiling," as was classical piano. I am currently working on the editing of a performance by Robert Silverman of Beethoven's Diabelli Variations, which I recorded in August 2004 in Utah using Ray Kimber's IsoMike baffling with matched Neumann M150 omni mikes. (This recording is scheduled to be released on CD in early summer 2005, with a surround SACD to be available sometime later.) With the master files played back on the Twenty-Fives, there was a palpable quality to the sound of Bob's Steinway that sounded deliciously real. Naturally recorded piano tends to highlight aberrations at the top of the woofer's passband in a two-way design, yet the Dynaudio's drive-units sounded well integrated in this region, without some notes jumping out at the listener. And again, the Dynaudio's low frequencies impressed with their weight and definition when Bob pounded away with his left hand in the Variation 32 fugue.

Stereo imaging was precise and stable, with a well-defined soundstage. Soundstage depth was less well developed at high frequencies than in the midrange. In fact, the upper midrange had a forward balance. And while the treble didn't sound bright per se, there was more high-frequency energy present than is called for by strict neutrality. While the differences between Billy Drummond's cymbals on "The Mooche" (from Jerome Harris' Rendezvous, Stereophile STPH013-2) were not obscured, they stood a little forward of the speaker plane. This was not in any way a problem with naturally balanced recordings—the Mozart flute-quartet and Brahms horn-trio tracks on Editor's Choice, for example. But on the more closely miked Mozart piano-quartet track on that CD, the violin and viola sounded a little wiry.

I can imagine this character being exacerbated by amplifiers and CD players that are themselves too hot in the treble, though the recessed low treble of many MC phono cartridges will tend to balance this characteristic of the Special Twenty-Five's balance. I did wonder if the forward treble would be alleviated by break-in, but while it seemed to diminish slightly over time, it didn't disappear. I found that listening slightly off the tweeter axis helped; with the speakers close to the sidewalls to reinforce the lows, I toed them in so that their tweeter axes crossed a foot or so ahead of my listening position. It is also important to note that this balance was not accompanied by any hardness or other fatiguing factor. The Special Twenty-Five's sound remained clean, even at high playback levels.

Summing up
Overall, the Dynaudio Special Twenty-Five is a superb loudspeaker, with a smooth, grain-free treble, a natural-sounding midrange, excellent soundstaging, and extended low frequencies when given a little bit of boundary reinforcement. However, its treble balance is on the forward side. In too live a room or with the wrong source and amplification components, that forward quality might well morph into brightness. No matter how much I occasionally wanted to give the Twenty-Five Stereophile's ultimate accolade on a specific piece of music where it shone new light, our Class B rating in "Recommended Components" was fundamentally correct, I believe.